2Y41

Structure of Isopropylmalate dehydrogenase from Thermus thermophilus - complex with IPM and MN


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.2 Å
  • R-Value Free: 0.224 
  • R-Value Work: 0.186 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Atomic Level Description of the Domain Closure in a Dimeric Enzyme: Thermus Thermophilus 3-Isopropylmalate Dehydrogenase.

Graczer, E.Merli, A.Singh, R.K.Karuppasamy, M.Zavodszky, P.Weiss, M.S.Vas, M.

(2011) Mol.Biosyst. 7: 1646

  • DOI: 10.1039/c0mb00346h
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • The domain closure associated with the catalytic cycle is described at an atomic level, based on pairwise comparison of the X-ray structures of homodimeric Thermus thermophilus isopropylmalate dehydrogenase (IPMDH), and on their detailed molecular gr ...

    The domain closure associated with the catalytic cycle is described at an atomic level, based on pairwise comparison of the X-ray structures of homodimeric Thermus thermophilus isopropylmalate dehydrogenase (IPMDH), and on their detailed molecular graphical analysis. The structures of the apo-form without substrate and in complex with the divalent metal-ion to 1.8 Å resolution, in complexes with both Mn(2+) and 3-isopropylmalate (IPM), as well as with both Mn(2+) and NADH, were determined at resolutions ranging from 2.0 to 2.5 Å. Single crystal microspectrophotometric measurements demonstrated the presence of a functionally competent protein conformation in the crystal grown in the presence of Mn(2+) and IPM. Structural comparison of the various complexes clearly revealed the relative movement of the two domains within each subunit and allowed the identification of two hinges at the interdomain region: hinge 1 between αd and βF as well as hinge 2 between αh and βE. A detailed analysis of the atomic contacts of the conserved amino acid side-chains suggests a possible operational mechanism of these molecular hinges upon the action of the substrates. The interactions of the protein with Mn(2+) and IPM are mainly responsible for the domain closure: upon binding into the cleft of the interdomain region, the substrate IPM induces a relative movement of the secondary structural elements βE, βF, βG, αd and αh. A further special feature of the conformational change is the movement of the loop bearing the amino acid Tyr139 that precedes the interacting arm of the subunit. The tyrosyl ring rotates and moves by at least 5 Å upon IPM-binding. Thereby, new hydrophobic interactions are formed above the buried isopropyl-group of IPM. Domain closure is then completed only through subunit interactions: a loop of one subunit that is inserted into the interdomain cavity of the other subunit extends the area with the hydrophobic interactions, providing an example of the cooperativity between interdomain and intersubunit interactions.


    Related Citations: 
    • Crystallization and Preliminary X-Ray Diffraction Analysis of Various Enzyme-Substrate Complexes of Isopropylmalate Dehydrogenase from Thermus Thermophilus.
      Merli, A.,Manikandan, K.,Graczer, E.,Schuldt, L.,Singh, R.K.,Zavodszky, P.,Vas, M.,Weiss, M.S.
      (2010) Acta Crystallogr.,Sect.F 66: 738


    Organizational Affiliation

    Institute of Enzymology, Biological Research Center, Hungarian Academy of Sciences, PO Box 7, H1518 Budapest, Hungary.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
3-ISOPROPYLMALATE DEHYDROGENASE
A, B
359Thermus thermophilus (strain HB8 / ATCC 27634 / DSM 579)Mutation(s): 0 
Gene Names: leuB
EC: 1.1.1.85
Find proteins for Q5SIY4 (Thermus thermophilus (strain HB8 / ATCC 27634 / DSM 579))
Go to UniProtKB:  Q5SIY4
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
MN
Query on MN

Download SDF File 
Download CCD File 
A, B
MANGANESE (II) ION
Mn
WAEMQWOKJMHJLA-UHFFFAOYSA-N
 Ligand Interaction
IPM
Query on IPM

Download SDF File 
Download CCD File 
A, B
3-ISOPROPYLMALIC ACID
C7 H12 O5
RNQHMTFBUSSBJQ-CRCLSJGQSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.2 Å
  • R-Value Free: 0.224 
  • R-Value Work: 0.186 
  • Space Group: C 2 2 21
Unit Cell:
Length (Å)Angle (°)
a = 50.240α = 90.00
b = 146.330β = 90.00
c = 175.210γ = 90.00
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
MOLREPphasing
REFMACrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2011-01-19
    Type: Initial release
  • Version 1.1: 2012-04-18
    Type: Database references